Raman spectroscopy of proteins: from peptides to large assemblies

Abstract

Raman spectroscopy has become a versatile tool in protein science and biotechnology. Recent advances in spectral assignments and vibrational theory, examples of use in structural biology and selected industrial applications are discussed. New insights into protein folding, assembly and aggregation were obtained by classical Raman spectroscopy. Raman spectroscopy has been used to characterize intrinsically unstructured proteins. The improved instrument sensitivity made it possible to use Raman difference spectroscopy to characterize enzyme-substrate interactions. Specifically, Raman crystallography has been instrumental in the delineation of protein-ligand interactions with a resolution surpassing that of x-ray diffraction. Numerous applications of Raman spectroscopy to protein analysis in biotechnology and food industry have been facilitated by the new generation of commercial Raman instruments.

Raman spectroscopy and multivariate analysis for the rapid discrimination between native-like and non-native states in freeze-dried protein formulations

“…Therefore, prior to visual inspection blank corrections and decomposition methods, Author-produced version of the article published in European Journal of Pharmaceutics and Biopharmaceutics, 2013, N°85(2), p. The original publication is available at http://www.sciencedirect.com/science/article/pii/S0939641113001264 Doi: 10.1016/j.ejpb.2013.03.035 such as Fourier deconvolution or second derivation of the spectra, have become popular to delineate overlapping secondary structures in the original spectrum [10]. As delineating is more complex in the blank corrected Raman spectra, the interpretation is frequently based on changes in peak shape rather than on individual band assignments [11][12][13]. Usually, the focus is on the visual interpretation of the well-known amide I and amide III bands.…”

Surface-enhanced Raman scattering and Plasmon effect for enzymatic bionanocomplexes characterization

“…Amide I and III lines are recorded at 1610 cm -1 [16] and at around 1220 cm -1 [18], however they are significantly weaker. Other lines at 1146 cm -1 , 800-900 cm -1 and 750 cm -1 can be attributed to the specific amino acids [19,20,21]. Some of the identified lines are not specific as a line at 1453 cm -1 associated witch CH vibration existing in linker and in protein structure as well [20].…”

“…Other lines at 1146 cm -1 , 800-900 cm -1 and 750 cm -1 can be attributed to the specific amino acids [19,20,21]. Some of the identified lines are not specific as a line at 1453 cm -1 associated witch CH vibration existing in linker and in protein structure as well [20]. Besides typical functional groups of proteins the vibration lines attributed to the Flavin adenine dinucleotide (FAD) cofactor have been observed (such as the adenine ring at 1343 and 1310 cm -1 [20], P-O around 1200 cm -1 and C=C binding at 1112 cm -1 ) [18].…”

H ferritin silencing induces protein misfolding in K562 cells: A Raman analysis

“…Finally, all spectra of the same group are averaged and only the spectral region between 1515 and 1775 cm -1 has been selected for further analysis of the proteins secondary structure. The other spectral regions are excluded due to the fact that some solvents used for As well known (14,15), the Amide I band mainly arises from the C=O stretching vibration of proteins backbone, and it is very sensitive to secondary structure. This Raman band is composed of three main peaks, centered at 1650-1655 cm -1 for alpha helix structures, at 1665-1670 cm -1 for the beta sheet, and 1675-1685 cm -1 for more disordered structures (15)(16)(17).…”

“…Lorentzian-Gaussian curves are used to model Raman peaks in the fitting procedure, using a Levenberg-Marquardt nonlinear least-squares method. As widely reported in literature (14)(15)(16)(17), the mixed Lorentzian-Gaussian curve is the best choice for fitting Raman peaks recorded on liquid samples, even with the DCDR technique where the solvent is partly evaporated. The starting parameters have been chosen so that three peaks are in the Amide I area, while two or three peaks are outside, corresponding to ring modes from aromatic side chains (in the range 1550-1615 cm -1 ) (18).…”